For those with limited access to grass, the following may be of interest.
Fodder Solutions is a way to grow your own feed using hydroponics.
From their own site:
"The system is a hydroponic growing room that has been specifically developed to sprout grain and legume seeds for highly nutritious yet cost effective livestock feed.
A selection of grains and legume seeds are spread onto the specialised growing trays and are watered at pre-determined intervals with overhead sprays. A set temperature is maintained inside the chamber to ensure the best growth and highest nutritional value fodder possible.
Each day you simply slide the feed out of the trays, rinse the tray, reseed and push the newly seeded tray into the other end. The system holds enough trays so your desired amount of feed is available everyday."
Importantly for Organics with Altitude, here's a Californian certified organic farmer using it: